WASHINGTON — The Pentagon’s ban on transgender troops would end May 27 under a draft timeline on repeal of the policy that affects about 12,000 troops, according to a document obtained by USA TODAY.

The memo, circulated last week among top personnel and medical officials, lays out the road map for ending the policy and highlights some of the potential issues, including a pilot program that would provide leaves of absences for transgender troops being treated with hormones or having surgery.

Meanwhile, Army and the Air Force leaders know for sure of about 20 transgender troops in each service, according to a Defense Department official familiar with the issue who spoke on condition of anonymity because officials were not authorized to speak publicly. The condition of gender dysphoria disqualifies them from service under current policy, but a de facto moratorium on dismissals was enacted last month by Defense Secretary Ash Carter.

Carter ordered a six-month review of the issues surrounding transgender troops with the assumption that they can serve openly unless “objective, practical impediments are identified,” the Aug. 19 memo says. During that period, one of Carter’s chief deputies would have to approve any request to discharge transgender troops.

The memo details a list of issues surrounding the open service of transgender troops, including medical treatment, housing, uniforms and physical fitness standards.

Earlier this month, a study in the New England Journal of Medicine by the Palm Center estimated that it would cost the military $5.6 million per year to treat transgender troops. The center, which studies issues of sexuality and the military, estimated that 188 of the 12,000 transgender troops would seek treatment in any given year. The number of transgender troops is an estimate; detailed numbers are harder to come by because troops have risked being discharged if they made their transgender status public.

Pentagon officials will consider a pilot program that would allow transgender troops under medical treatment to take a sabbatical from service, returning to the ranks after they have made their transition to the other gender. They must also decide whether transgender troops being treated are eligible for deployment to war zones, the memo says.

Also under consideration: revisiting the discharge status of transgender troops who have been kicked out of the service. It is unclear how many troops have been discharged over the years for the condition because the Pentagon does not track them. A dishonorable discharge for having gender dysphoria could affect employment opportunities and veterans benefits.

Some top officers complained that the military has been asked to enact too much social change in recent years, including the 2011 repeal of the military’s ban on gay and lesbian troops serving openly, and on the continuing integration of women into combat units, said the Defense official and a colleague, who also spoke on condition of anonymity because they weren't authorized to speak publicly.

Many senior officers, however, want a clear policy on transgender troops, the Defense officials said. These officers are comfortable with rules that allow them to keep good troops with gender dysphoria and provide them treatment.